Unpack all *.m files into the same directory. When starting Octave, select the "current directory" the same as the one where you put the *.m files.
Then type LeafSpy_UI in command window and press ENTER. The main GUI windows appears where you can choose your preferences.

After clicking "Load file and calculate", one of your Log files should be selected. The results are then plotted. Red vertical lines on the graphs (if they appear) represent time gaps in measurements.